1720, Scottish, "magic, enchantment" (especially in phrase to cast the glamor), a variant of Scottish gramarye "magic, enchantment, spell," alteration of English grammar (q.v.) with a medieval sense of "any sort of scholarship, especially occult learning," the latter sense attested from c.1500 in English but said to have been more common in Medieval Latin. Popularized by the writings of Sir Walter Scott (1771-1832). Sense of "magical beauty, alluring charm" first recorded 1840. Jamieson's 1825 supplement to his "Etymological Dictionary of the Scottish Language" has glamour-gift "the power of enchantment; metaph. applied to female fascination." Jamieson's original edition (1808) looks to Old Norse for the source of the word. Zoega's Old Icelandic dictionary has glám-sýni "illusion."

The word glamour (magic charm, alluring beauty or charm, a spell affecting the eye, a kind of haze in the air) comes from the Scottish term gramarye (magic, enchantment, spell), an alteration of the English word grammar (any sort of scholarship) from the latin grammatica, which is a transliteration of the Greek word grammatice (grammar; γραμματική).

"Poetry is a kind of witchcraft. We have the power to manifest, to call forth, to make what didn’t happen, happen. I think of the griots who delivered stories from town to town, the soothsayers and playwrights and brujas, all the ceremonies and dedications and incantations and proclamations, everything that starts with the word. And how the word gains its power by being spoken and handed to the next person and how what we write will last longer than our skins, our poems are the truest husks of our former selves."
'Rachel McKibbens, from the interview “What We Write Will Last Longer Than Our Skins” by Leah Umansky for Tin House

as ideas son como las pulgas, saltan de unos a otros pero no pican a todos".

Grammar (n.)

early 14c., gramarye (late 12c. in surnames), from Old French gramaire "learning," especially Latin and philology, "grammar, (magic) incantation, spells, mumbo-jumbo," "irregular semi-popular adoption" [OED] of Latin grammatica, from Greek grammatike tekhne "art of letters," with a sense of both philology and literature in the broadest sense, fem. adjective from gramma "letter," from stem of graphein "to draw or write" (see -graphy). An Old English word for it was stæfcræft (see staff (n.)).
Form grammar is from late 14c. Restriction to "rules of language" is a post-classical development, but as this type of study was until 16c. limited to Latin, Middle English gramarye also came to mean "learning in general, knowledge peculiar to the learned classes" (early 14c.), which included astrology and magic; hence the secondary meaning of "occult knowledge" (late 15c.), which evolved in Scottish into glamor (q.v.).
A grammar school (late 14c.) originally was "a school in which the learned languages are grammatically taught" [Johnson, who also has grammaticaster "a mean verbal pedant"]. In U.S. (1842) the term was put to use in the graded system for "a school between primary and secondary where English grammar is taught."

GLOSSary

SPELL

early 14c., "read letter by letter, write or say the letters of;" c. 1400, "form words by means of letters," apparently a French word that merged with or displaced a native Old English one; both are from the same Germanic root, but the French word had evolved a different sense. The native word is Old English spellian "to tell, speak, discourse, talk," from Proto-Germanic *spellam (cognates: Old High German spellon "to tell," Old Norse spjalla, Gothic spillon "to talk, tell"), from PIE *spel- (2) "to say aloud, recite."

But the current senses seem to come from Anglo-French espeller, Old French espelir "mean, signify, explain, interpret," also "spell out letters, pronounce, recite," from Frankish *spellon "to tell" or some other Germanic source, ultimately identical with the native word.

Related: Spelled; spelling. In early Middle English still "to speak, preach, talk, tell," hence such expressions as hear spell "hear (something) told or talked about," spell the wind "talk in vain" (both 15c.). Meaning "form words with proper letters" is from 1580s. Spell out "explain step-by-step" is first recorded 1940, American English. Shakespeare has spell (someone) backwards "reverse the character of, explain in a contrary sense, portray with determined negativity."

The term 'spell' is generally used for magical procedures which cause harm, or force people to do something against their will -- unlike charms for healing, protection, etc. ["Oxford Dictionary of English Folklore"]

The terms "witch" and "wise woman" actually had their origins in ancient Kemet (Egypt's true name, meaning Land of the Blacks). Wadj (or Uadj) is a Kemetic word meaning "power, health, green, water." A wadj scepter represents a tied bundle of herbs for health and prosperity. A variant of the word is Udja (pronounced WOO-jah), where the term Ouija board is also derived from.
Neb-t Het). Wadjet (Uadjet, Uachet) is a term for a strong magickal woman who can suddenly bend energy for healing.

CHARM

Middle English (in the senses ‘incantation or magic spell’ and ‘to use spells’): from Old French charme (noun), charmer (verb), from Latin carmen ‘song, verse, incantation.’

charm (n.)
c. 1300, "incantation, magic charm," from Old French charme (12c.) "magic charm, magic, spell; incantation, song, lamentation," from Latin carmen "song, verse, enchantment, religious formula," from canere "to sing" (see chant (v.)), with dissimilation of -n- to -r- before -m- in intermediate form *canmen (for a similar evolution, see Latin germen "germ," from *genmen). The notion is of chanting or reciting verses of magical power.
A yet stronger power than that of herb or stone lies in the spoken word, and all nations use it both for blessing and cursing. But these, to be effective, must be choice, well knit, rhythmic words (verba concepta), must have lilt and tune; hence all that is strong in the speech wielded by priest, physician, magician, is allied to the forms of poetry. [Jacob Grimm, "Teutonic Mythology" (transl. Stallybrass), 1883]
Sense of "pleasing quality" evolved 17c. Meaning "small trinket fastened to a watch-chain, etc." first recorded 1865. Quantum physics sense is from 1964. To work like a charm (figuratively) is recorded by 1824.
charm (v.)
c. 1300, "to recite or cast a magic spell," from Old French charmer (13c.) "to enchant, to fill (someone) with desire (for something); to protect, cure, treat; to maltreat, harm," from Late Latin carminare, from Latin carmen (see charm (n.)). In Old French used alike of magical and non-magical activity. In English, "to win over by treating pleasingly, delight" from mid-15c. Related: Charmed; charming. Charmed (short for I am charmed) as a conventional reply to a greeting or meeting is attested by 1825.